A swimming activity assay shows that the thermal tolerance of Daphnia magna is influenced by temperature acclimation

2004 ◽  
Vol 82 (10) ◽  
pp. 1605-1613 ◽  
Author(s):  
Bettina Zeis ◽  
Jana Maurer ◽  
Olaf Pinkhaus ◽  
Eva Bongartz ◽  
Rüdiger J Paul

Daphnia magna Straus, 1820 is a widespread zooplanktic organism enduring considerable changes in oxygen concentration and temperature within its natural habitat. The thermal tolerance window of D. magna was analyzed using the animals' swimming activity as a test parameter in a photometrical assay. Acclimation to different temperatures (10, 20, 30 °C) resulted in a shift of the thermal optimum corresponding to acclimation conditions. Acclimation to warm temperatures also increased the upper thermal tolerance limit in acute thermal tolerance tests. However, the magnitude of the resulting shift in the acute thermal tolerance (LT50) was much smaller. An increase in acclimation temperature by 10 °C changed the thermal optimum by approximately this value, whereas the LT50 was enhanced only by 1–2 °C. The time course of the acclimation process was followed by surveying temperature-dependent swimming activity upon the transfer of animals raised in a medium at 20 °C to a medium at 30 °C. Maximum swimming intensity at 20 °C was lost within 3 days. The swimming behavior resembled that of animals acclimated to 30 °C after 2 weeks, indicating that acclimation to the elevated temperature was achieved.

1994 ◽  
Vol 267 (4) ◽  
pp. R1150-R1153 ◽  
Author(s):  
J. A. Segal ◽  
D. L. Crawford

The temperature-dependent expression of lactate dehydrogenase-B (LDH-B) was compared between two environmentally distinct populations of Fundulus heteroclitus acclimated to 10 degrees C and 20 degrees C. The variability in LDH-B protein expression both within and between populations is consistent with a model of thermal compensation. The northern population from the colder environment expresses a twofold greater amount of LDH-B protein than the warmer southern population at both acclimation temperatures. Correspondingly, both populations have 1.3-fold greater levels of the enzyme at an acclimation temperature of 10 degrees C in comparison to 20 degrees C. In 20 degrees C-acclimated individuals there is a similar twofold difference between populations for LDH-B mRNA concentrations, and LDH-B protein and mRNA are highly correlated (r = 0.81). After acclimation to 10 degrees C, this difference between populations is not seen and in the northern population there is no relationship between LDH-B mRNA and protein levels. Thus the molecular mechanism regulating LDH-B enzyme expression changes in response to temperature acclimation and is different between populations.


2021 ◽  
Vol 8 (7) ◽  
pp. 210440
Author(s):  
Melissa K. Drown ◽  
Amanda N. DeLiberto ◽  
Moritz A. Ehrlich ◽  
Douglas L. Crawford ◽  
Marjorie F. Oleksiak

To better understand temperature's role in the interaction between local evolutionary adaptation and physiological plasticity, we investigated acclimation effects on metabolic performance and thermal tolerance among natural Fundulus heteroclitus (small estuarine fish) populations from different thermal environments. Fundulus heteroclitus populations experience large daily and seasonal temperature variations, as well as local mean temperature differences across their large geographical cline. In this study, we use three populations: one locally heated (32°C) by thermal effluence (TE) from the Oyster Creek Nuclear Generating Station, NJ, and two nearby reference populations that do not experience local heating (28°C). After acclimation to 12 or 28°C, we quantified whole-animal metabolic (WAM) rate, critical thermal maximum (CT max ) and substrate-specific cardiac metabolic rate (CaM, substrates: glucose, fatty acids, lactate plus ketones plus ethanol, and endogenous (i.e. no added substrates)) in approximately 160 individuals from these three populations. Populations showed few significant differences due to large interindividual variation within populations. In general, for WAM and CT max , the interindividual variation in acclimation response (log 2 ratio 28/12°C) was a function of performance at 12°C and order of acclimation (12–28°C versus 28–12°C). CT max and WAM were greater at 28°C than 12°C, although WAM had a small change (2.32-fold) compared with the expectation for a 16°C increase in temperature (expect 3- to 4.4-fold). By contrast, for CaM, the rates when acclimatized and assayed at 12 or 28°C were nearly identical. The small differences in CaM between 12 and 28°C temperature were partially explained by cardiac remodeling where individuals acclimatized to 12°C had larger hearts than individuals acclimatized to 28°C. Correlation among physiological traits was dependent on acclimation temperature. For example, WAM was negatively correlated with CT max at 12°C but positively correlated at 28°C. Additionally, glucose substrate supported higher CaM than fatty acid, and fatty acid supported higher CaM than lactate, ketones and alcohol (LKA) or endogenous. However, these responses were highly variable with some individuals using much more FA than glucose. These findings suggest interindividual variation in physiological responses to temperature acclimation and indicate that additional research investigating interindividual may be relevant for global climate change responses in many species.


Chemosphere ◽  
2019 ◽  
Vol 216 ◽  
pp. 805-811 ◽  
Author(s):  
Adam Bownik ◽  
Michał Kowalczyk ◽  
Jan Bańczerowski

2010 ◽  
Vol 42 (2) ◽  
pp. 103 ◽  
Author(s):  
Zulfaidah Penata Gama ◽  
Pablo Morlacchi ◽  
Giuseppe Carlo Lozzia ◽  
Johann Baumgärtner ◽  
Anna Giorgi

The spatial distribution of Aphis spiraecola Patch was studied in two commercial yarrow fields located in the Swiss and Italian Alps and represented by Taylor’s (1961) power law. The respective parameters indicate a highly aggregated distribution and lead to a high optimum sample size of 400-500 plants in the design of a sampling program. Opportunities for reducing the sampling efforts are discussed. The infestation patterns were studied on the basis of Vansickle’s (1977) time varying distributed delay adequate for modelling the dynamics of age-structured populations. Published literature data were used to parametrize the functions representing the temperature-dependent duration and survival of the nymphal and adult stage. Likewise, literature data were available to obtain reliable estimates for the parameters of the fecundity function comprising the reproductive profile and the number of nymphs produced at different temperatures. The field data were used to parametrize the functions for wing formation and a compound mortality compromising the effects of plant senescence, stem cutting and natural enemies. The model satisfactorily represented the observed infestation patterns. However, there are opportunities for improving parameter estimation and validation. Moreover, the separation of the compound mortality into host plant and natural enemy effects would improve the mechanistic basis of the model and lead towards a tool that could be used to study bottom-up and top-down effects in the yarrow-aphid-natural enemy system.


2020 ◽  
Vol 2 (1) ◽  
pp. 37-42
Author(s):  
Arunachalam M ◽  
Thamilmaran P ◽  
Sakthipandi K

Lanthanum calcium based perovskites are found to be advantageous for the possible applications in magnetic sensors/reading heads, cathodes in solid oxide fuel cells, and frequency switching devices. In the present investigation La0.3Ca0.7MnO3 perovskites were synthesised through solid state reaction and sintered at four different temperatures such as 900, 1000, 1100 and 1200˚ C. X-ray powder diffraction pattern confirms that the prepared La0.3Ca0.7MnO3 perovskites have orthorhombic structure with Pnma space group. Ultrasonic in-situ measurements have been carried out on the La0.3Ca0.7MnO3 perovskites over wide range of temperature and elastic constants such as bulk modulus of the prepared La0.3Ca0.7MnO3 perovskites was obtained as function of temperature. The temperature-dependent bulk modulus has shown an interesting anomaly at the metal-insulator phase transition. The metal insulator transition temperature derived from temperature-dependent bulk modulus increases from temperature 352˚ C to 367˚ C with the increase of sintering temperature from 900 to 1200˚ C.


2001 ◽  
Vol 204 (1) ◽  
pp. 39-45 ◽  
Author(s):  
F.B. Jensen ◽  
T. Wang ◽  
J. Brahm

Unidirectional (36)Cl(−) efflux via the red blood cell anion exchanger was measured under Cl(−) self-exchange conditions (i.e. no net flow of anions) in rainbow trout Oncorhynchus mykiss and red-eared freshwater turtle Trachemys scripta to examine the effects of acute temperature changes and acclimation temperature on this process. We also evaluated the possible adaptation of anion exchange to different temperature regimes by including our previously published data on other animals. An acute temperature increase caused a significant increase in the rate constant (k) for unidirectional Cl(−) efflux in rainbow trout and freshwater turtle. After 3 weeks of temperature acclimation, 5 degrees C-acclimated rainbow trout showed only marginally higher Cl(−) transport rates than 15 degrees C-acclimated trout when compared at the same temperature. Apparent activation energies for red blood cell Cl(−) exchange in trout and turtle were lower than values reported in endothermic animals. The Q(10) for red blood cell anion exchange was 2.0 in trout and 2.3 in turtle, values close to those for CO(2) excretion, suggesting that, in ectothermic animals, the temperature sensitivity of band-3-mediated anion exchange matches the temperature sensitivity of CO(2) transport (where red blood cell Cl(−)/HCO(3)(−) exchange is a rate-limiting step). In endotherms, such as man and chicken, Q(10) values for red blood cell anion exchange are considerably higher but are no obstacle to CO(2) transport, because body temperature is normally kept constant at values at which anion exchange rates are high. When compared at constant temperature, red blood cell Cl(−) permeability shows large differences among species (trout, carp, eel, cod, turtle, alligator, chicken and man). Cl(−) permeabilities are, however, remarkable similar when compared at preferred body temperatures, suggesting an appropriate evolutionary adaptation of red blood cell anion exchange function to the different thermal niches occupied by animals.


1987 ◽  
Vol 129 (1) ◽  
pp. 107-123 ◽  
Author(s):  
A. P. Farrell

A preparation was developed to perfuse the coronary circulation in working hearts from rainbow trout (Salmo gairdneri Richardson). The preparation was used to examine pressure-flow relationships for the coronary circulation as the heart generated physiological and subphysiological work loads. Coronary vascular resistance increased exponentially as coronary flow rate decreased. Coronary resistance was also influenced by cardiac metabolism and acclimation temperature. When heart rate was increased, extravascular compression increased in coronary resistance. Direct vasoconstriction of the coronary vessels, produced by injections of adrenaline into the coronary circulation, was temperature-dependent.


1977 ◽  
Vol 69 (1) ◽  
pp. 13-21
Author(s):  
DENNIS J. MURPHY

1. A time course of the changes in blood Ca2+ and freezing tolerance of Modiolus demissus (Dillwyn) demonstrated that increases in freezing tolerance parallel increases in blood Ca2+. The increases in freezing tolerance occurred rapidly, suggesting that Ca2+ affects freezing tolerance directly by its presence in the blood. 2. The presence of La3+ reduced the freezing tolerance of isolated foot muscle. Thus, Ca2+ appears to increase freezing tolerance directly by binding to cell membranes. 3. The loss of the contractile response of freeze-thawed foot muscle to Ach, KCl and caffeine and the continued response to CaCl2 suggested that cell membranes are the primary sites of freezing injury. 4. The increase in blood Ca2+ following low-temperature acclimation accounted for only 40% of the total change in freezing tolerance. Therefore, other mechanisms responsible for increasing the freezing tolerance of M. demissus following low temperature acclimation also exist.


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